Cooling means for tunnel-kilns



J. B. OWENS.

COOLING MEANS FOR TUNNEL KILNS.

APPLICATION FILED AUG. I4. 19H

Patented May 31, 1921.

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CGOLING MEANS FOR TUNNEL-KILNS.

Specification of Letters Patent.

Patented May 31, 1921.

Original application filed July 15, 1916, Serial No. 109,511. Divided and this application filed August To aZZ whom it may concern e it known that 1, JOHN B. Owens, a citizen of the United States, residing at Metuchen, in the county of Middlesex and State of New Jersey, have invented certain new and useful Tm )rovements in Cooling Means for Tunnel-l ilns, of which the following is a specification.

This invention relates to cooling means for tunnel kilns and this application is a division of my application for kilns, Serial No. 109,511, filed uly 15,1916.

In a tunnel kiln, the ware having passed through a high temperature, and being burned, in the burning or firing zone, it must cool gradually to prevent destruction of, or damage to, the ware but such cooling must be sutliciently rapid to insure adequate production by the kiln of the ware treated.

T he object of the present invention is to provide improved cooling means in a tunnel kiln which will enable the ware to be cooled at a relatively rapid rate without damage thereto by utilizing the heat radiated from the burned ware to the end that it is carried off without cool air coming in direct contact with the ware. The ware, being thus deprived of its heat, absorbed during the burning or firing operation, cools rapidly and without damage.

The practical embodiment of my invention comprises air spaces in the walls of the cooling zone of the tunnel, provided with air inlets for outer, cool air to be admitted to their lower portions, and outlets for voiding air from their upper portions. Either a natural draft, or an induced draft, may be employed in connection with the air spaces. The ware, previously burned in the firing zone, having reached the cooling zone of the tunnel kiln, the heat radiated from the ware against the inner faces of the tunnel walls is carried off by the cool air passing upwardly in the air spaces in said walls. This cool air, by reason of its upward circulation, cools the inner walls of the tunnel, and the heat radiated from the ware is attracted to the inner wall and carried off.

The construction used for providing the air spaces or air channels in the walls of the tunnel at the cooling zone may be varied. Such spaces or channels may be provided within the walls themselves, or, as separate ducts or conduits. I do not, therefore, limit myself to the precise embodiment of the in- Serial No. 249,826.

vention hereinafter described and which is shown in the drawings and the same is to be considered as illustrative, instead of restrictive, of the scope of the invention.

In the accompanying drawings:

Figure 1 is a side elevation of a tunnel kiln which is provided with my invention;

Fig. 2, is a transverse sectional view taken through the cooling zone on the plane indicated by the line 2-2 in Fig. 1; and

Fig. 3 is a horizontal sectional detail view taken on the line 33, Fig. 2.

To illustrate the position my improvements occupy in a tunnel kiln, I have shown in Fig. 1 the side of a tunnel kiln A having air locks 18 and 19 at its entrance and exit ends, respectively, provided with movable gates, not shown, which may be raised and lowered, as desired, and provided with cables 21 and counterweights 22.

The drying zone is shown, generally, at 23, the burning zone at 30, furnace at 31, and the cooling zone to which my improvements apply, at 43.

The cars which convey the goods or ware through the kiln from left to right, Fig. 1, travel on rails 57, Fig. 3.

Any suitable stack or draft inducing leans, not shown, may be employed to aiford the requisite draft necessary in a kiln of this character.

Any suitable fuel may be used for the furnace 31. There is shown means for utilization of producer gas supplied by a main 32 to branches 33, 35 which lead to the furnace where the gas is burned.

My improvements relating to' the cooling zone will now be described, said improve ments constituting the present invention.

The walls of the cooling zone 43 are lined with hollow construction 44, producing vertical tubes or ducts 45 that communicate at their lower ends with air inlets 46 in the side walls of the kiln, Figs. 2 and 3, the upper ends of the tubes or ducts 45 comnninicating with openings 47 in the lower roof arch 48 which is separated by an intervening space 49 from the upper roof arch 50 which has one or more outlets 51, permitting a circulation of air which will reduce the temperature of the cooling zone, thereby permitting the ware to become gradually cooled during its passage through said zone and prior to its discharge through the air lock 19.

Circulation through the ducts 4:5 and the space 49 may be accelerated by supplying air under pressure, as by means of a blower,

conventionally indicated at 49 in Fig. 2,

or in other convenient manner. The effect of this would be to cool the burned material more rapidly and to produce a larger supply of heated air for other purposes.

The outlet 51 may communicate with ducts 38 for the purpose of conveying to the furnace 31 the air which has become heated during its passage through the ducts 45. The circulation through ducts 38 may be induced vor forced.

The ware,previously burned in the firing zone having reached the cooling zone 43, the heat radiated from the ware against the inner faces of the ducts 45 through which cool are is traveling upwardly, is carried off by the cool air in said ducts and passes out through the outlet or out,- lets 51, either to the air, or to any suitable point. The cool air in the ducts 45 cools the inner walls of the tunnel throughout the cooling zone a3 and the heat radiated from the ware is attracted to the inner walls of aforesaid and is carried off, sufiiciently slowly to prevent damage to the ware and yet with such rapidity that the ware is cooled-with a speed suitable to insure relatively rapid output of cooled ware from the kiln-on operation of the air lock arch L8 completely seals the cooling zone 43 from the outer air and from the space 49. There is no direct outer-air inlet into the cooling zone, nor any direct air-outlet from said zone to chill the ware. The cooling action is solely an indirect one and yet is relatively rapid.

Whether the tubes or .ducts a5 are provided in the walls of the cooling zone, or in a hollow construction arranged as a lining therefor, the numerous ducts divide up the air into numerous streams, facilitating the cooling action.

WVhat I claim is:

1. A tunnel kiln having a furnace for delivering heat into the interior of its tunnel The off the heat radiated from the ware within the cooling zone without direct entry of air into said cooling zone or direct'exit ofair therefrom. e V

2. A tunnel kiln having a furnace for delivering heat into the interior of its tunnel and provided with a sealed cooling zone whose side walls are provided with numerous air circulating ducts sealed from the interior of the cooling zone, said duets being adapted to receive outer air at their lower parts, and to Void the air at their upper parts, and being arranged and adapted for the upward passage of the outer air for the purpose of cooling the inner vtunnel walls and taking off the heat radiated from the ware within the cooling zone without direct entry of air into said cooling zone or direct exit of air therefrom.

3. A tunnel kiln having a furnace for delivering heat into the interior of its tunnel, a sealed cooling zone whose side walls are provided with air circulating spaces sealed from the interior of the cooling zone, said spaces being adapted to receive outer air at their lower parts, and to void the air at their upper parts,'and being arranged and adapted for the upward passage of the outer air for the purpose of cooling the inner tunnel walls and taking off the heat radiated from the ware within the cooling zone without direct entry of air into said cooling zone or direct exit of air therefrom, and means for conducting the voided heated air from said air circulating spaces to the furnace of the kiln. V

In testimony whereof I atlix my signature.

JOHN B. OWENS. 

